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| Registros recuperados: 16 | |
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| Koedam, N.; Dahdouh-Guebas, F.; De Wulf, R.; Tack, J.; Obade, P.T.. |
| Historic environmental, faunal, floral and socioeconomic data of Gazi Bay in coastal Kenya were collated and integrated into a GIS environment and data of impacts due to various factors were then related to remotely sensed data. Rhizophora mucronata, a valuable mangrove species, was investigated. Very low values of basal area (7.7 m2/ha and 4.9 m2/ha) and complexity indices (1.86 and 1.12) at Makongeni and Kinondo 1, respectively, reflected intense human pressure in these areas. Areas that were easily accessible or close to human settlements appeared more vulnerable. Accrued information from a socioeconomic survey carried out over the same period corroborates the hypothesis that human influence was a major contributor to these changes. Historic aerial... |
| Tipo: Journal Contribution |
Palavras-chave: Ecology; Environmental monitoring; Mangroves; Fauna; Satellite imagery; Environmental impact; Http://aims.fao.org/aos/agrovoc/c_24420. |
| Ano: 2004 |
URL: http://hdl.handle.net/1834/1087 |
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| Riitters, Kurt; U.S. Forest Service; kriitters@fs.fed.us; Wickham, James D; U.S. Environmental Protection Agency, National Exposure Research Laboratory; wickham.james@epa.gov; O'Neill, Robert; ; eoneill@attglobal.net; Jones, K. Bruce; U.S. Environmental Protection Agency, National Exposure Research Laboratory; jones.bruce@epa.gov; Smith, Elizabeth; U.S. Environmental Protection Agency, National Exposure Research Laboratory; smith.betsy@epa.gov. |
| We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 x 9 pixels, “small” scale) to 59,049 km 2 (243 x 243 pixels, “large” scale) were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined) from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents,... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Biogeography; Edge effect; Forest fragmentation; Geographic information systems; Global patterns; Land-cover map; Landscape ecology; Modeling; Perforated forest; Remote sensing; Satellite imagery; Spatial pattern. |
| Ano: 2000 |
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| Picoli,Michelle Cristina Araujo; Duft,Daniel Garbellini; Machado,Pedro Gerber. |
| Abstract: The objective of this work was to evaluate the potential of several spectral indices, used on moderate resolution imaging spectroradiometer (Modis) images, in identifying drought events in sugarcane. Images of Terra and Aqua satellites were used to calculate the spectral indices, using visible (red), near infrared, and shortwave infrared bands, and eight indices were selected: NDVI, EVI2, GVMI, NDI6, NDI7, NDWI, SRWI, and MSI. The indices were calculated using images between October and April of the crop years 2007/08, 2008/09, 2009/10, and 2013/14. These indices were then correlated with the standardized precipitation-evapotranspiration index (SPEI), calculated for 1, 3, and 6 months. Four of them had significant correlations with SPEI: GVMI,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum officinarum; Drought stress; Image processing; Satellite imagery; SPEI; Warning systems. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017001101063 |
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| Fleming, David A.. |
| The Conservation Reserve Program (CRP) is the largest land retirement program ever operated in the US. Since its inception in 1985, many researchers have studied the impacts of this program; however, only a few have analyzed how the CRP affects surrounding non–enrolled parcels. In this research I examine how the CRP may affect the conversion of non–cropped land to agriculture, a phenomenon referred to as “slippage” in the literature, and specifically addressed by Wu (2000) and Roberts and Bucholtz (2005). Building on these earlier studies, I empirically model slippage using data derived from satellite imagery that provides information on land cover changes between 1992 and 2001. The study area consists of 1,053 counties located in the Northern Plains, Corn... |
| Tipo: Working or Discussion Paper |
Palavras-chave: CRP; Land use change; Satellite imagery; Slippage effect; Agricultural and Food Policy; Land Economics/Use; Q15; Q24. |
| Ano: 2010 |
URL: http://purl.umn.edu/61394 |
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| Espinosa Espinosa, José Luis. |
| La tarea de los sistemas de asesoramiento de riego suele ser costosa en recursos humanos y materiales por la necesidad de hacer un seguimiento intensivo en campo, en áreas extensas y se suele enfrentar al reto de transferir la información al usuario, agricultor o técnico, en la vía adecuada y en el momento oportuno. Asimismo, las nuevas tecnologías de observación de la tierra, ha contribuido a que millones de hectáreas sean monitoreadas mediante sensores a bordo de satélites siendo más eficaz el seguimiento en campo, ya que proporcionan imágenes de la superficie terrestre. De igual forma las tecnologías de la información, el internet y la telefonía móvil, permiten que la información generada por los sistemas de asesoramiento de riego, incluida la imagen... |
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Palavras-chave: Sensores remotos; Imágenes de satélite; Indice de vegetación; NDVI; Visor web; Remote sensing; Satellite imagery; Vegetation index; Web viewer; Hidrociencias; Maestría. |
| Ano: 2013 |
URL: http://hdl.handle.net/10521/2135 |
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| Nivens, Heather D.; Kastens, Terry L.; Dhuyvetter, Kevin C.. |
| Remotely sensed data have been used in the past to predict crop yields. This research attempts to incorporate remotely sensed data into a net farm income projection model. Using in-sample regressions, satellite imagery appears to increase prediction accuracy in the time periods prior to USDA's first crop production estimate for wheat and corn. Remotely sensed data improved model performance more in the western regions of the state than in the eastern regions. However, in a jackknife out-of-sample framework, the satellite imagery appeared to statistically improve only 8 of the 81 models (9 crop reporting districts by 9 forecasting horizons) estimated. Moreover, 41 of the 81 models were statistically better without the satellite imagery data. This indicates... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Net farm income; Remote sensing; Satellite imagery; Crop Production/Industries. |
| Ano: 2000 |
URL: http://purl.umn.edu/18943 |
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| Registros recuperados: 16 | |
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